[gold][aarch64] PR gold/19987 - gold segfaults on R_AARCH64_LD64_GOTPAGE_LO15

[Cary Coutant]

> Hi Cary, this patch for pr 19987 fixes / implements the
> R_AARCH64_LD64_GOTPAGE_LO15.
>
> Tested by running doit.sh provided by reporter. (Runtime test is not
> done because even the provided "correct" binary crashed on my system.
> Khen, are you able to test it?)
>
> gold/ChangeLog:
>
>     PR/19987.
>
>     * aarch64-reloc.def: New relocation type.
>     * aarch64.cc (AArch64_relocate_functions::Page): Changed to public.
>     (Target_aarch64::Scan::local): Add R_AARCH64_LD64_GOTPAGE_LO15.
>     (Target_aarch64::Scan::global): Add R_AARCH64_LD64_GOTPAGE_LO15.
>     (Target_aarch64::Relocate::relocate): Implement R_AARCH64_LD64_GOTPAGE_LO15.
>
> OK for trunk?

OK. Thanks!

-cary